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KCET2022ChemistryChemical Kinetics

A first order reaction is half completed in 45 ~min . How long does it need 99.9 % of the reaction to be completed ?

Options

  1. A7.5 Hours
  2. B10 Hours
  3. C20 Hours
  4. D5 Hours

Correct answer

A. 7.5 Hours

Step-by-step solution

t_ 1 / 2 for first order reaction is 45^ min t_ 1 / 2 = 0.693 k k= 0.693 I_ 1 / 2 = 0.693 45 aligned t & = 2.303 k a a-x = 2.303 0.693 45 100 0.1 & =448 min 7.5 hrs . aligned

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